The overall goal of this CHAVI application is to elucidate viral and host determinants of HIV-1 transmission, persistence, and partial containment in primary human infection, and to translate these findings into rational vaccine design. Core A will support this effort by providing expertise and service in the areas of host genomics and HIV-1 genetics. The Core is comprised of three sections: 1. The Host Genomics Section (under the leadership of Dr. David Goldstein) will elucidate host genetic differences affecting susceptibility to HIV-1 infection and disease progression in early HIV-1 infection. Specific tasks include to (i) identify, validate, and genotype a robust set of tagging SNPs (tSNPs) for 500 high priority human genes to facilitate indirect genetic association studies, (ii) identify putative functional variants among the candidate genes for direct association studies;(iii) develop uniform experimental genotyping approaches;(ivj optimize sequencing primers for direct association studies in the rhesus monkey;(v) investigate all associations at the genetic and functional level;and (vi) establish a robust data management system for clinical as well as host and viral genetic data. 2. The HIV-1 Molecular Biology and Sequencing Section (under the leadership of Dr. Beatrice Hahn), will generate functional HIV-1 env clones and full-length HIV-1 sequences from acutely and chronically infected individuals to elucidate the genetic, biologic, antigenic, and structural characteristics of sexually transmitted virus and the mechanisms underlying this transmission. Specific tasks include to (i) amplify, clone and sequence functional env genes from acute HIV-1 infections;(ii) examine envelopes from acute and chronic HIV-1 infections for phenotypic differences, and (iii) derive full-length HIV-1 sequences from patients with acute HIV-1 infection. 3. The HIV-1 Computational Biology and Biostatistics Section (under the leadership of Bette Korber), will provide interactive automated HIV-1 sequence entry and analysis tools, and establish and maintain an Acute HIV-1 Sequence Database. Specific tasks include to (i) provide an interactive automated HIV-1 sequence data entry system that enables users to identify sequencing errors and contamination as part of their initial data processing;(ii) provide interactive automated tools for baseline analysis/of CHAVI HIV-1 sequences, (iii) make CHAVI HIV-1 sequences publicly available, (iv) build CHAVI investigator interfaces for data entry of immunological data, (v) analyze HIV-1 sequence datasets for acute infection sequence signatures and (vi) provide statistical support for the CHAVI effort. In Year 02, each of these sections will become an independent core facility (see Strategic Plan), commensurate with the anticipated increase of both host and HIV-1 sequence analysis.